Currently, it is common for enterprise networks to utilize virtual local area networks (hereinafter referred to as “VLANs”). A “VLAN” is a group of client devices that are adapted to communicate as if these devices were connected to the same broadcast domain irrespective of their actual physically location. Configured through software rather than hardware, VLANs provide flexibility as to allow a client device, without any hardware reconfiguration, to retain its membership on the same VLAN even though it is physically moved from one location to another.
VLAN pooling is an abstraction of the assignment of client devices to different VLANs. Currently, one issue with VLAN pooling is that it may cause the transmission of duplicate multicast streams over a wireless shared media. In infrastructure mode, when VLAN pooling is used, wireless client devices for a particular Basic Service Set (BSS), which is identified by a specific BSS Identifier (BSSID), may be randomly allocated to one or more different VLANs. Hence, wireless client devices on the same BSSID but assigned to different VLANs will likely receive duplicate multicast streams.
More specifically, an upstream multicast router sends a copy of a multicast stream for each VLAN for which a wireless client device has registered to receive multicast packets. These duplicated multicast streams are routed to an access point (AP) of a targeted BSS for wireless transmission. As a result, wireless client devices on the same BSSID and different VLANs will receive duplicate multicast streams for the same multicast group.
Based on current VLAN pooling operations, it is quite possible for multiple client devices in the same multicast group to end up on different VLANs. In a worst case scenario, for a VLAN pool with “n” VLANs, the multicast router will provide “n” copies of multicast streams for transmission via the AP. Such duplication leads to a substantial increase in over-the-air channel utilization, resulting in a waste of wireless spectrum.
A method of mitigating multicast stream duplication when using VLAN pooling techniques is needed.